Vacuum cleaner bag



1968 R. c. LAGERSTROM 3,

VACUUM CLEANER BAG Filed June 28, 1965- V INVENTOR. fiz faberi :gemfimg United States Patent 3,364,663 VACUUM CLEANER BAG Robert C. Lagerstrom, Normal, Ill., assignor to Nationm Union Electric Corporation, Stamford, Conn, a corporation of Delaware Filed June 28, 1965, Ser. No. 467,504 3 Claims. (Cl. 55-389) This invention relates to improvements in a vacuum cleaner of the type having a disposable filter bag.

Disposable filter bags for vacuum cleaners are made of a special grade of porous paper having the required combination of strength and filtering characteristics. As is well known, when the cleaner is in operation, dirty air is drawn in through the nozzle of the cleaner by suction means and is dischaged into the interior of the filter bag, and the clean air passes through the porous walls of the bag leaving the dirt trapped inside the bag. The movement of the air through the paper bag causes the latter to expand or balloon outwardly during operation of the cleaner, but when the motor-blower unit of the cleaner is turned oft the paper filter bag collapses or deflates as the passage of air ceases. During continued usage of the cleaner, the pressure and movement of the air passing through the bag walls tends to drive particles of dirt into the fine pores of the bag at the inside thereof and as a result the pores of the filter bag often become clogged even though the bag itself may be only partially full. Thus, the pressure drop between opposite sides of the bag walls increases, the air flow rate through the bag is diminished, and the filtering or dirt removal capacity of the filter bag is impaired. In addition, an excessive load may be placed on the motor because of the clogged bag.

Accordingly, a primary object of the present invention is to provide novel and improved means for overcoming the clogging tendency of disposable filter bags in vacuum cleaners. v

A further object of the invention is to provide a novel bag arrangement for a vacuum cleaner which has improved operating and dirt-removing characteristics.

An additional object of the invention is to provide a novel declogging action in a vacuum cleaner having a disposable filter bag.

Other objects and advantages of the invention will become apparent from the subsequent detailed description taken in conjunction with the accompanying drawing, wherein:

FIG. 1 is a perspective view of an upright type vacuum cleaner embodying the present invention and showing the condition of the bag when the cleaner is inoperative:

. FIG. 2 is a perspective view of the same cleaner when in operation;

FIG. 3 is a longitudinal sectional view through the bag portion of the cleaner in its FIG. 2 operating condition; and

FIG. 4 is a similar view of the bag portion of the cleaner when the cleaner is in its FIG. 1 nonoperating condition.

In the usual upright vacuum cleaner of the disposable filter bag type, the dirt-laden air passes upwardly into the lower end of an elongated internal paper bag which is surrounded by an elongated exterior cloth or plastic bag. The air passes outwardly through the walls of the paper bag where the dirt particles are trapped and the clean air then escapes to the outside atmosphere by passage through the exterior bag. When the inner paper bag becomes filled with dirt, it is removed from the permanent exterior bag and a replacement paper bag is installed. As mentioned above, there is a tendency for the pores of the paper filter bag to become clogged with dirt particles long "ice before the bag itself is full enough to require replacement. The frequent bumps or jars accompanying normal use of the cleaner will tend to shake loose some of the dirt adhering to the inner walls of the paper filter bag but will not dislodge the dirt particles which have been driven into the pores of the bag.

In accordance with the present invention, the permanent exterior bag which encloses the disposable paper bag is made of resiliently stretchable or elastic material such that it is resiliently expanded by the internal paper bag as the latter balloons outwardly or inflates when the cleaner is in operation. Thereafter, when the cleaner is shut off, the outer stretchable bag retracts with a re silient action thereby positively collapsing the walls of the paper bag so as to forcibly dislodge dirt particles from the pores of the bag. The dirt removal is effected each time the cleaner is operated and shut oil so that the tendency toward clogging of the filter bag walls is minimized thereby maintaining high efiiciency of dirt removal and avoiding undue load on the electric motor.

Referring to the drawing, an upright cleaner It} is shown having the usual wheeled body or housing 11 containing an intake nozzle (not shown) for dirt-laden air and a motor-blower unit (not shown) for creating a suction at the nozzle. An operating switch 12 is provided for turning the cleaner on and off. The usual elongated handle 13 is pivotally secured to the body 11 and is provided with hooks 14 for supporting the usual electric cord 16 when the cleaner is not in use, as seen in FIG. 1.

A permanent exterior bag 17 is provided in the form of an elongated tubular sleeve having a closed upper end 18. The lower end of the bag 17 has a restricted mouth portion 19 which is permanently aifixed to a tubular connector 21. The connector 21 is detachably mountable (by means not shown) at the air discharge outlet of the cleaner body 11. An elongated disposable paper filter bag 22 is located inside of the permanent exterior bag 17 and also has a closed upper end 23 and a restricted mouth 24 at its lower end, the mouth 24 being detachably fitted on the connector 21. The upper end 18 of the outer bag 17 is detachably supported on the handle 13 by means of an elongated spring 25 or other similar connector.

The disposable bag 22 is of a familiar type comprising a strong porous grade of filter paper and is preferably provided with a plurality of folds or pleats which permit expansion of the bag from an initial flattened condition to an enlarged condition. The permanent outer bag 17 is formed from a resiliently expansible or elastic material, such as rubberized fabric or a suitable stretchable plastic, and has a plurality of small openings or perforations 26 so that the outer bag is air permeable. When the cleaner is turned on, dirt-laden air is drawn in through the housing 11 and is discharged through the tubular connector 21 into the interior of the paper bag 22. Prior to passage of air through the cleaner, the bag 22 is in a compressed or deflated condition, as seen in FIG. 4. However, as air is forced through the porous walls of the bag 22 during operation of the cleaner, there is suflicient resistance to the flow of air to cause the bag 22 to balloon outwardly to an expanded or inflated condition, as seen in FIG. 3.

In a conventional upright cleaner, the outer permanent bag of the cleaner is nonstretchable but has a fixed size which is large enough to accommodate the expanded paper bag. However, in accordance with the present invention, the normal or unexpanded volume of the elastic outer bag 17 is less than the volume of the inflated paper bag so that the elastic outer bag is resiliently expanded or pushed outwardly by the walls of the paper bag when the latter inflates, as shown in FIG. 3. The filtered air then escapes through the paper bag walls and passes through the perforations 26 in the outer bag 17 into the surrounding atmosphere.

As previously explained, dirt particles are retained by the porous filter paper of the bag 22, and with continued usage the pores of the paper tend to become clogged or obstructed so that the efiiciency of the cleaner is diminished even though the disposable bag itself may not be filled to capacity. In conventional cleaners this condition must be tolerated except to the extent that normal handling of the cleaner may shake loose or displace some of the dirt adhering to the inner Walls of the paper bag. However, with the present invention, when the cleaner is shut off so that the flow of air is suddenly stopped and the inflating force on the paper bag disappears, the resiliently stretched outer bag 17 retracts rapidly and the walls thereof snap back to normal unstretched position. This rapid elastic retraction causes the walls of the outer bag to forcibly engage and collapse the paper bag walls thereby dislodging or knocking the dirt from the pores of the paper. It will be appreciated that each time the cleaner is shut off the disposable paper bag is subjected to this self'cleaning action so that the filtering efficiency of the paper bag and the overall efliciency of the cleaner are maintained at a high level.

When the disposable bag 22 is full it is removed in the usual manner by detaching the spring 25 and the connector 21 from the cleaner, opening the usual slide fastener (not shown) in the side of the exterior bag 17, and then withdrawing the mouth 24 of the paper bag 22 from the connector 21.

Although the invention has been described with particular reference to the illustrated embodiment thereof, it is to be understood that various equivalents and modifications may be resorted to without departing from the scope of the invention as defined in the appended claims.

I claim:

1. In a vacuum cleaner having motor operated suction means for drawing in dirt-laden air and discharging the same through a filtering means during operation of the motor and for terminating the flow of air when the motor is shut olf, the improvement comprising the combination of an inner filter bag having walls of porous paper for filtering dirt-laden air passing from the interior to the exterior thereof, and an outer container of resiliently stretchable and air permeable material surrounding said filter bag, said filter bag being inflatable to a predetermined size in response to passage of air therethrough and said outer container when in unstretched condition being smaller than said predetermined size but being resiliently expandable in response to inflation of said filter bag, whereby when air flow through said filter bag is terminated, said outer container resiliently retracts to its unstretched condition and forcibly collapses said filter bag thereby dislodging dirt from the Walls thereof.

2. In a vacuum cleaner having motor operated suction means for drawing in dirt-laden air and discharging the same through a filtering means during operation of the motor and for terminating the flow of air when the motor is shut off, the improvement which comprises an inner filter bag having porous filter paper walls and adapted to have dirt-laden air introduced into the interior thereof, the walls of said filter bag offering sufiicient resistance to the flow of air therethrough to cause said filter bag to inflate to a predetermined size during operation of the cleaner, and an outer bag of resiliently stretchable and air permeable material surrounding said inner filter bag, said outer bag in unstretched condition being smaller than said predetermined size of the inflated filter bag whereby said outer bag is resiliently expanded in response to inflation of said filter bag and whereby said outer bag resiliently retracts to its unstretched condition when air flow through said filter bag is terminated, thereby forcibly collapsing said filter bag and dislodgin-g dirt from the walls thereof.

3. In an upright vacuum cleaner having motor operated suction means for drawing in dirt-laden air and discharging the same through a discharge outlet during operation of the motor and for terminating the flow of air when the motor is shut off, an improved filter bag arrangement for filtering said dirt-laden air comprising an elongated disposable filter bag with porous filter paper Walls and having a mouth portion for the introduction of dirt-laden air into the interior of the filter bag and passage of clean air through the bag walls leaving dirt at the inside of said walls, said filter bag being inflatable to predetermined size in response to the passage of air therethrough, an elongated permanent outer bag surrounding said filter bag and having an air inlet, and means for detachably connecting said mouth portion and said air inlet to the cleaner outlet, said outer bag being air permeable and resiliently stretchable and when in unstretched condition being smaller than said predetermined size of the inflated filter bag so as to be expanded by the walls of said filter bag as the latter inflates during the passage of air therethrough, and said outer bag being resiliently retractable to its unstretched condition When the flow of air through said filter bag is terminated whereby to forcibly collapse said filter bag and dislodge dirt from the walls thereof.

References Cited UNITED STATES PATENTS 428,853 5/ 1890 McCaffrey et a1 299-55 798,680 9/1905 Jackson 22955 1,828,584 10/1931 Anderson 55-380 X 2,312,999 3/1943 De Langen 55--293 2,514,280 7/1950 Hammell 55382 2,593,328 4/1952 Meaker 229--55 2,779,433 1/1957 Winslow 55304 X 2,951,553 9/1960 Kirby 55361 HARRY B. THORNTON, Primary Examiner.

B. NOZICK, Assistant Examiner. 

1. IN A VACUUM CLEANER HAVING MOTOR OPERATED SUCTION MEANS FOR DRAWING IN DIRT-LADEN AIR AND DISCHARGING THE SAME THROUGH A FILTERING MEANS DURING OPERATION OF THE MOTOR AND FOR TERMINATING THE FLOW OF AIR WHEN THE MOTOR IS SHUT OFF, THE IMPROVEMENT COMPRISING THE COMBINATION OF AN INNER FILTER BAG HAVING WALLS OF POROUS PAPER FOR FILTERING DIRT-LADEN AIR PASSAGE FROM THE INTERIOR TO THE EXTERIOR THEREOF, AND AN OUTER CONTAINER OF RESILIENTLY STRETCHABLE AND AIR PERMEABLE MATERIAL SURROUNDING SAID FILTER BAG, SAID FILTER BAG BEING INFLATABLE TO A PREDETERMINED SIZE IN RESPONSE TO PASSAGE OF AIR THERETHROUGH AND SAID OUTER CONTAINER WHEN IN UNSTRETCHED CONDITION BEING SMALLER THAN SAID PREDETERMINED SIZE BUT BEING RESILIENTLY EXPANDABLE IN RESPONSE TO INFLATION OF SAID FILTER BAG, WHEREBY WHEN AIR FLOW THROUGH SAID 